Sanitary napkin with porous resin powder deodorant

ABSTRACT

A sanitary napkin containing at least one layer of staple fibers having adhered thereto, as a deodorant, a porous resin powder in the form of its acid salt, the resin having been produced by the condensation of an aromatic amine, with or without a phenol, with formaldehyde. The sanitary napkin containing the layer is particularly effective in deodorizing a malodorous liquid.

[ Dec. 24, 1974 United States Patent 1191 Yamauchi 88R Raw 88 2,634,2294/1953 (16 Wet 2,643,969 6/1953 Mahon....... 2,837,462 6/1958 M01111Aklra Yamauchl, y g J p 3,691,271 9/1972 Charle 61 a1. Assignee: JexCo., Ltd., Osaka-fu, Japan Filed:

T WN A R 0 PD A0 NE D mm m n m NW MPm M 4% U, U

Primary Examiner-Richard A. Gaudet [22] 1972 Assistant ExaminerJ. C.McGowan Appl. No.: 317,795 Attorney, Agent, or FirmStewart and Kolasch,Ltd.

[30] Foreign Application Priority Data Oct. 23, 1972 A sanitary napkincontaimng at least one layer of stal28/290, 424/28 ple fibers havingadhered thereto, as a deodorant, a

porous resin powder in the form of its acid salt, the resin having beenproduced by the condensation of an [51] Int. A6lf 13/16 [58] Field ofSearch 128/284, 286, 287, 290,

128/296, 285; 424/27 28 aromatic amine, with or without a phenol, withformaldehyde. The sanitary napkin containing the layer is particularlyeffective in deodorizing a malodorous liquid.

[56] References Cited UNITED STATES PATENTS 2,418,907 4/1947Schreiber....................... 128/290 R 15 Claims, 1 Drawing FigureSANITARY NAPKIN WITH POROUS RESIN POWDER DEODORANT and retention of themalodorous fluid on sanitary napkins, the conventional sanitary napkinshave not been satisfactory. Although some napkins have a thick layer orseveral layers which function to adsorb the fluid, they still possessthe problem of the exudation of the malodorous fluid therefrom.

It is an object of the present invention to provide a sanitary napkincontaining a deodorant which is effective in deodorizing a malodorousfluid.

Another object of the present invention is to provide a sanitary napkinwhich contains at least one layer of staple fibers to which a deodorantpowder in the form of its acid salt is adhered, said napkin functioningto absorb the malodorous constituents of a fluid.

A further object of the present invention is to provide a sanitarynapkin which is effective in adsorbing and diffusing a malodorous fluid.

Still another object of the present invention is to provide a sanitarynapkin which although being thin in thickness and small in size, isnevertheless effective in maintaining the desired deodorizing andadsorbing effects.

Other objects, features and advantages of the present invention willbecome apparent during the course of the description which follows, andthe accompanying drawing wherein The FIGURE is a perspective view of asanitary napkin according to the present invention.

Referring now more particularly to the FIGURE, element I0 is a non-wovenfabric, 11 is a water-adsorbing paper, 12 is a wate r-repellent paper,13 is a water-proof paper, 14 is a thread, and 15 is a sheet made ofstaple fibers which contain the deodorant powder of the presentinvention.

As shown in the FIGURE the non-woven fabric 10 is made in the form of aclosed container, which acts as a wrapper to protect the materialscontained therein and help them retain their shape. As seen in the FIG-URE two sheets of water-adsorbing paper 11, a sheet of staple fibers 15,another two sheets of wateradsorbing paper 11, another sheet of staplefibers 15, two sheets of water-repellent paper 12 and a sheet ofwater-proof paper 13 are piled together in this order, and a sheet ofwater-repellent paper 12 is positioned at both sides of the accumulatedmaterials so as to substantially cover said sides. The materials arearranged in such a way that the upper side of the water-adsorbing paper11 is next to the inner side of that portion of the wrapper which doesnot contain the thread, as illustrated in the FIGURE. Both the opensides are sealed at an appropriate length. The side of the napkincontaining the thread 14 is the exterior side of the napkin, and as suchshould not come into contact with the body of the user. Only theopposite or interior side of the napkin should contact the body of theuser.

The materials and shapes of the non-woven fabric, the water-adsorbingpaper, the water-repellent paper, the water-proof paper and the threadconventionally employed and known in the art may also be used for thesanitary napkin of the present invention, and no limitav tions areplaced on these materials and shapes unless undesirable effects can beexpected by their use. The essential feature of the present invention isthat at least one of the layers or sheets of the napkin is made ofstaple fibers which contain a specific deodorant powder. Advantageously,the sanitary napkin of the present invention is arranged as shown in theaccompanying drawing although some modifications and rearrangements ofthe materials and shape may be possible without decreasing the desiredeffects to be attained. For example, a sheet of staple fibers containingactivated carbon powder may be used for either of two sheets of staplefibers 15. Alternatively, it is also possible that the deodorant powderof the invention is disposed in the water-adsorbing papers between thetwo sheets of staple fibers 15. The shape of the wrapper is also notlimited to that specifically disclosed in the accompanying drawing, andvarious modifications and arrangements can be contrived to meetpractical needs.

Although the specific embodiment of the present in- The deodorant powdermay be used alone or as a mixture with other water-absorbing agentsand/0r fillers known in the art. The deodorant of the present inventionis a porous resin produced from an aromatic amine, with or without aphenol, by condensation with formaldehyde. The condensation product hasas a partial structure the following chemical structure:

NHI NH:

OH OH I i i -CH CH: CH: CH:

NH: NH:

I OH

The resin may be specifically produced from starting materials, such forexample, one mole of m-phenylene diamine, one mole of phenol orresorcin, and three moles of formaldehyde, using as a catalyst an acid,such for example, hydrochloric acid or oxalic acid, in substantially thesame manner as utilized in conventional processes of manufacturingphenolic resins. As starting materials, m-aminophenol and formaldehyde,may also be used, without the presence of a phenol. A porous structureof the resin may be accomplished by the addition of a conventionalaqueous inorganic salt to the reaction system at the beginning of thereaction. The re sulting resin is then heat-treated at above 80C. forabout hours in the air and thereafter is washed by a hot alkalineaqueous solution and then by dilute hydrochloric acid, resulting in theremoval of intermediate condensates.

The porous resinous powder of the present invention is stable in water,solutes and alkalis, and is not decomposable at temperatures below 100C.Said resin is capable of holding a comparably large amount of water inits structure as will be clear from the hydrophilic property of theamino groups on the aromatic rings and its porous structure. When theresin is employed in the napkin of the present invention, the content ofwater is preferably about 30 to 50 per cent.

The resin of the present invention is in the form of its acid salt forpractical use. The acid salt may be produced by neutralizing the aminogroups in the resin with acids. The following is a reaction schemeshowing the neutralization reaction.

wherein R is a resin body and X is a residue of an acid.

The acids which can be used for the neutralization of the resingenerally are those which are not harmful to human beings, such astartaric acid. Although the acid used for the neutralization of theresin is liberated in the water in a very small amount, a napkincontaining the deodorant of the present invention does not cause anyharm to the user because of the presence of the acid liberated in thewater contained in the napkin. It should also be noted that nodissolution of other substances such as, for example, formaldehydeoccurs.

The functions of deodorizing various malodorous constituents by thedeodorant are considered as follows: 1. Basic malodorous constituentssuch as ammonia, amines, and the like: The malodorous constituents arefirst dissolved in the water contained in the deodorant and then reactedwith acids adhered to the resin to form an odor-free salt. For example,ammonia is converted to a malodor-free salt as follows:

R-N H ,-X* R-NH +HX in which R and X are as given above. The resultingresin is then reacted with the acidic malodorous constituents having thefollowing general formula: HY, in

which Y is a residue of the acid, whose reaction is represented asfollows:

This means that the acidic malodorous constituents are adsorbed by theresin, resulting in the formation of the acid salt free from malodor. 3.Neutral malodorous constituents such as aromatic hydrocarbons: Theneutral malodorous constituents may be deodorized by intramolecular,physical adsorption because the deodorant is porous and it has a verylarge surface area.

In accordance with the present invention, said deodorants having theabove-mentioned adsorbing properties possess a more effective adsorbingcapacity when compared to deodorants conventionally available in theart. As compared with a slightly acidic cationexchange resin, thedeodorants of the present invention have the capacity of adsorbingacetic acid about 3 to 4 times more than the cation-exchange resin.Furthermore, the cation-exchange resin has no adsorbing capacity forhydrogen sulfide, as do the deodorants of the present invention. As forstrongly basic anion-exchange resins, the deodorants of the presentinvention adsorb ammonia approximately 30 times more than the basicaninon-exchange resin and they show an adsorbing capacity fortrimethylamine, whereas the basic anionexchange resin has no suchcapacity. Compared with active carbon made from coconuts, the deodorantsof the present invention have about 3 to 4 times the adsorbing capacityfor ammonia as said activated coconut carbon, and about 4 to 5 times theadsorbing capacity for acetic acid. Furthermore, the ammonia that wasadsorbed on the active coconut carbon at 10C. was desorbed in an amountof about to per cent, when the active carbon was heated to 50C. On theother hand, the ammonia adsorbed by the deodorants of the presentinvention was only slightly desorbed, that is, in an amount of about 1to 2 per cent under the same conditions.

These characteristics of the deodorants according to the presentinvention are based upon the following facts; l the resin is anamphoteric ion-exchange resin, not a mere anion-exchange resin; (2) itsexchange groups (R-NH and R-OH) act as weak electrolytes; and (3) a gastends to penetrate into the resin because of its porous structure.

In conventional ion-exchange resins, for example, a cation-exchangeresin having strongly acidic exchange groups can easily adsorb basicmalodorous constituents, but it does not adsorb acidic malodorousconstituents because the repellency of the homogenous electric chargesof the strong exchange groups of the cationexchange resin and the acidicmalodorous constituents makes it difficult for the constituents totransfer into the liquid phase in the resin. However, the resin of thepresent invention has weak exchange groups, thereby making it capable ofadsorbing both acidic and basic malodorous constituents.

When the deodorants of the present invention were applied to themenstruous discharge, it was confirmed by gas-chromatography thatmonomethylamine, methyl mercaptan, ethylamine, acetaldehyde, acrolein,diethylamine, ethyl mercaptan, n-butylaldehyde, nbutyl mercaptan, etc.were adsorbed. This shows the removal of a majority of the malodorousconstituents of the discharge.

ln accordance with the present invention, the deodorants may be employedalone or as a mixture with unharmful agents, such as diatomaceous earth,conventionally employed in the art as a water-adsorbent or filler..These additives may be used in an amount of about 10 to 20' parts byweight, preferably 16 parts by weight, with respect to one part byweight of the deodorant.

The layer or sheet of the present invention is made out of staple fibersas a support to which the deodorant powder alone or as a mixture with awater-adsorbent or filler is adhered. The staple fibers may be the sameas those employed for conventional sanitary napkins, such as cottonlinter and the like. Pulp fiber is particularly preferred. The staplefibers may be used in an amount of about 50 to 500 parts by weight,preferably 200 parts by weight, with respect to a part by weight of thedeodorant. Said sheet may be prepared by spreading a ground pulp bandwith the deodorant powders. However, the deodorant powders tend to peeloff or drop from the sheet prepared in this manner causing a decrease inthe desired deodorizing effect. The preferred preparation of the sheetis accomplished by a procedure discussed hereinbelow. The procedureenables the deodorants to adhere adhesively to the fiber. Thesatisfactory adherence effect may be produced by scattering the powderduring ventillation of the pulp by a pulp machine following conventionalpurification procedures. More particularly, the desired sheet of pulpfibers and the deodorant may be prepared from pulp bands in aconventional manner by maintaining the deodorant powders and the groundpulp in a fluidized state in a wind pipe. The deodorant powders areintroduced into the wind pipe through a powder supply pipe and thepowders are joined in the pipe with the ground pulp which is ventilatedinto the wind pipe through a crusher. Since the pulp fibers are chargedwith static electricity created by the friction of the hammers in thecrushing device, the deodorant powders adhere to the surface of eachfiber while the mixture is fluidized in the wind pipe. Microscopicobservations of a sheet manufactured by the above procedures show thatparticles of an adhering agent, such as diatomaceous earth, and thelike, form complex surfaces which adhere to the pulp fibers morestrongly than the deodorant powder. Accordingly, the use of an adheringagent prevents the adhering deodorant powder from becoming detached fromthe fibers during the handling.

The sanitary napkin having the features described above permits a fluidto penetrate through the nonwoven fabric and the water-adsorbing paperinto the surface of the sheet of staple fibers containing the deodorantpowder. Here the fluid spreads itself into the sheet while beingadsorbed and diffused by the combined action of the liquid-adsorbingaction of said powder itself and the liquid-adsorbility between thefibers with their effective liquid adsorbing surfaces increased by theadherence of the powder thereon. Accordingly, the fluid is effectivelydeodorized by contact with the deodorant powder adhered to the surfacesof each of said fibers. In addition, agaseous malodor generated from thefluid is also adsorbed by the deodorant powder. Furthermore, the fluidspreads and distributes itself in the napkin not only in the verticaldirection (depth direction) but also in the horizontal direction (theplane direction) resulting in an increase in the amount of liquid whichcan be adsorbed. Thus the napkin of the present invention can be reducedin size while still maintaining the effective deodorant capacity. Saidadvantages were confirmed by an organoleptic test using a napkin ofnormal size (a total weight of 6.5 to 7 grams) having the same shape andstructure as shown in the accompanying drawing, and containing 0.02 gramof the deodorant powder, 0.28 gram of diatomaceous earth and 4 grams ofpulp staple fibers.

What is claimed is:

1. In a sanitary napkin which comprises at least one layer of staplefibers in the form of a pad, the improvement wherein said pad containsas a deodorant a porous resin powder which is the condensation productof an aromatic amine with fonnaldehyde in the form of its acid salt.

2. The sanitary napkin according to claim 1 wherein a phenol is presentin the reaction system.

3. The sanitary napkin according to claim 1 wherein the condensationproduct is one layer made of a pulp staple fiber containing an aromaticamine selected from the group consisting of m-phenylenediamine andm-aminophenol, with or without phenol or resorcin, and formaldehyde,said reaction product being in the form of the salt of tartaric acid.

4. The sanitary napkin according to claim 3, wherein the deodorantpowder is produced from mphenylenediamine and phenol or resorcin bycondensation with formaldehyde.

5. The sanitary napkin according to claim 4, wherein one mole ofm-phenylenediamine, one mole of phenol or resorcin and three moles offormaldehyde are used.

6. The sanitary napkin according to claim 3, wherein the deodorantpowder is produced from maminophenol by condensation with formaldehyde.

7. The sanitary napkin according to claim 3, wherein a pulp staple fiberis used in an amount of about 50 to 500 parts by weight with respect toone part by weight of the deodorant powder.

8. The sanitary napkin according to claim 3, wherein the amount of thepulp staple fiber is about 200 parts by weight with respect to about onepart by weight of the deodorant powder.

9. The sanitary napkin according to claim 4, wherein the deodorantpowder is used in an amount of about one part by weight with respect toabout 10 to 20 parts by weight of diatomaceous earth.

10. The sanitary napkin according to claim 9, wherein the amount ofdiatomaceous earth is about 16 parts by weight to about one part byweight of the deodorant powder.

11. The sanitary napkin according to claim 1, comprising a composite oftwo layers of water-adsorbing paper, a layer of staple fibers, anothertwo layers of water-adsorbing paper, another layer of staple fibers, twolayers of water-repellent paper and a layer of waterproof paper whichare arranged in this order, said composite being provided at both sidesthereof with a layer of water-repellent paper.

12. The sanitary napkin according to claim 1 comprising one layer ofstaple fibers containing said deodorant, said layer being surrounded onone side with at least one layer of water-repellant paper and on theother side with at least one layer of water absorbing paper.

13. The sanitary napkin according to claim 1 comprising two layers ofstaple fibers containing said deodorant, said layers being separated byat least one layer of water absorbing paper and surrounded on one sidewith at least one layer of water-repellant paper and on the other sidewith at least one layer of water absorbing paper.

14. The sanitary napkin of claim 12 housed within a non-woven fabricwrapper.

15. The sanitary napkin of claim 13 housed within a non-woven fabricwrapper.

1. IN A SANITARY NAPKIN WHICH COMPRISES AT LEAST ONE LAYER OF STAPLEFIBERS IN THE FORM OF A PAD, THE IMPROVEMENT WHEREIN SAID PAD CONTAINSAS A DEODORANT A POROUS RESIN POWDER WHICH IS THE CONDENSATION PRODUCTOF AN AROMATIC AINE WITH FORMALDEHYDE IN THE FORM OF ITS ACID SALT. 2.The sanitary napkin according to claim 1 wherein a phenol is present inthe reaction system.
 3. The sanitary napkin according to claim 1 whereinthe condensation product is one layer made of a pulp staple fibercontaining an aromatic amine selected from the group consisting ofm-phenylenediamine and m-aminophenol, with or without phenol orresorcin, and formaldehyde, said reaction product being in the form ofthe salt of tartaric acid.
 4. The sanitary napkin according to claim 3,wherein the deodorant powder is produced from m-phenylenediamine andphenol or resorcin by condensation with formaldehyde.
 5. The sanitarynapkin according to claim 4, wherein one mole of m-phenylenediamine, onemole of phenol or resorcin and three moles of formaldehyde are used. 6.The sanitary napkin according to claim 3, wherein the deodorant powderis produced from m-aminophenol by condensation with formaldehyde.
 7. Thesanitary napkin according to claim 3, wherein a pulp staple fiber isused in an amount of about 50 to 500 parts by weight with respect to onepart by weight of the deodorant powder.
 8. The sanitary napkin accordingto claim 3, wherein the amount of the pulp staple fiber is about 200parts by weight with respect to about one part by weight of thedeodorant powder.
 9. The sanitary napkin according to claim 4, whereinthe deodorant powder is used in an amount of about one part by weightwith respect to about 10 to 20 parts by weight of diatomaceous earth.10. The sanitary napkin according to claim 9, wherein the amount ofdiatomaceous earth is about 16 parts by weight to about one part byweight of the deodorant powder.
 11. The sanitary napkin according toclaim 1, comprising a composite of two layers of water-adsorbing paper,a layer of staple fibers, another two layers of water-adsorbing paper,another layer of staple fibers, two layers of water-repellent paper anda layer of water-proof paper which are arranged in this order, saidcomposite being provided at both sides thereof with a layer ofwater-repellent paper.
 12. The sanitary napkin according to claim 1comprising one layer of staple fibers containing said deodorant, saidlayer being surrounded on one side with at least one layer ofwater-repellant paper and on the other side with at least One layer ofwater absorbing paper.
 13. The sanitary napkin according to claim 1comprising two layers of staple fibers containing said deodorant, saidlayers being separated by at least one layer of water absorbing paperand surrounded on one side with at least one layer of water-repellantpaper and on the other side with at least one layer of water absorbingpaper.
 14. The sanitary napkin of claim 12 housed within a non-wovenfabric wrapper.
 15. The sanitary napkin of claim 13 housed within anon-woven fabric wrapper.